晶面可控钛基SCR脱硝催化剂结构设计及反应机制研究

The principle and technology for selective catalytic reduction of NOx in coal-fired flue gas is an important topic in the scientific research of environmental chemistry. In this project, TiO2 support with controllable morphology and facet will firstly be synthesized, then active components will be loaded on the specific facets of TiO2 support to develop novel titania-based NH3-SCR DeNOx catalyst. The SCR activity of the prepared catalysts will be regulated by assembling and modulating the functional nanostructure on the interface of the catalysts. Under simulated flue-gas conditions, the catalytic performances of DeNOx catalysts will be evaluated. The effects of H2O and SO2 on catalytic performance will be investigated systematically. The optimized catalysts will exhibit superior DeNOx properties, such as low-temperature reactivity, poisoning-resistance, thermal stability and excellent product selectivity. Some important factors involved in the reaction, such as active center, electron transfer, intermediates, transition state will be investigated systematically with a variety of methods, especially in situ characterization methods. The relationship of composition, structure and catalytic activity of the catalysts will be explored. The reaction mechanism of NH3-SCR over titania-based DeNOx catalyst with controllable morphology and facet will be revealed on the micro level by the combined experimental and computational study. The program can not only promote the development of novel environmental catalysts, but also provide a theoretical and practical basis for developing effective SCR denitration control technology.

燃煤烟气中NOx削减技术及控制原理的研究是目前环境化学领域研究的热点。本项目拟合成形貌和晶面可控的TiO2载体，调控活性组分在TiO2特定晶面的落位，制备出钛基NH3-SCR脱硝催化剂。组装、调控基于TiO2特定晶面的功能纳米结构，调变SCR脱硝的反应性能。模拟燃煤烟气污染特征，评价钛基NH3-SCR催化剂的脱硝活性及H2O、SO2等对SCR脱硝性能的影响，优化出低温活性高、抗中毒性能强、热稳定性好、产物安全的新型高效SCR脱硝催化剂。综合利用多种分析技术，特别是原位表征技术，获取反应过程中的活性中心、电子转移、中间物种和反应过渡态等重要信息。系统研究催化剂的组成、结构与催化活性之间的构效关系，并结合量子化学计算模拟，从微观层次深入探究形貌和晶面可控的钛基NH3-SCR催化剂脱硝反应机理。本项目不仅对新型环境催化剂的研制起到推动作用，还将为NOx的污染控制技术提供一种新的方法和理论依据。

本项目设计、合成了一种优先暴露{001}晶面的TiO2载体，通过负载VOx、MnOx、SmOx等纳米金属氧化物活性组分，制备出了高效去除NOx的纳米片NH3-SCR复合脱硝催化剂；通过组装、调控基于TiO2特定晶面的功能纳米结构，实现了较低温度条件下对氮氧化物的高效、安全、快速的选择性催化还原。制备了V-WOx/TiO2复合纳米催化剂，考察了该催化剂选择性还原的反应性能。设计合成了高效的Sm-MnOx/TiO2复合纳米催化剂，系统研究了该催化剂选择性催化还原一氧化氮（Nitric oxide, NO）的反应活性，综合利用多种表征手段系统研究了催化剂的构效关系，深入探究了催化反应的内在机制。采用原位红外光谱技术，解析了催化反应过程的中间物种，并提出了催化剂表面NH3吸附和选择性催化还原NO的机理。本项目为NOx的污染控制技术提供一种新的方法和理论依据。